foam-extend4.1-coherent-io/applications/solvers/solidMechanics/elasticPlasticNonLinTLSolidFoam/writeHistory.H

//- write force displacement to file
if(historyPatchID != -1)
  {
    Info << "Writing disp-force to file for patch " << historyPatchName
      << endl;

     //- for small strain or moving mesh
     //scalar force = gSum(
     //            direction &
     //            (mesh.boundary()[historyPatchID].Sf() & sigma.boundaryField()[historyPatchID])
     //            );

     //- for large strain total lagrangian
     tensorField F = I + gradU.boundaryField()[historyPatchID];
     vector force = gSum(mesh.Sf().boundaryField()[historyPatchID] & (sigma.boundaryField()[historyPatchID] & F));
     vector disp = gAverage(U.boundaryField()[historyPatchID]);


    Info << "Writing strain-stress to file for patch " << historyPatchName
      << endl;

     // avaerage stress strain
     symmTensor stress = gAverage(sigma.boundaryField()[historyPatchID]);
     symmTensor strain = gAverage(epsilon.boundaryField()[historyPatchID]);


     // write to file
     if(Pstream::master())
       {
     OFstream& forceDispFile = *forceFilePtr;
     label width = 20;
     forceDispFile << disp.x() << " " << disp.y() << " " << disp.z();
     forceDispFile.width(width);
     forceDispFile << force.x() << " " << force.y() << " " << force.z()
               << endl;

     OFstream& stressStrainFile = *stressFilePtr;
     stressStrainFile << strain.xx() << " " << strain.xy() << " " << strain.xz() << " "
              << strain.yy() << " " << strain.yz() << " " << strain.zz();
     stressStrainFile.width(width);
     stressStrainFile << stress.xx() << " " << stress.xy() << " " << stress.xz() << " "
              << stress.yy() << " " << stress.yz() << " " << stress.zz()
              << endl;
       }
   }